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I spent hours getting "null" results in joining a downloaded state and county shp file to a self-created file (SCF). What I found was that the SCF had to have "EXACTLY" the same set of names/ID#'s as did the shp file. Is there a way for the join algorithm to scan a list, identify an equal, move to the next, identify an equal, move to the next, not identify an equal; AND then move to the next such that the whole system doesn't in effect shut down and give NULL values for all? Abstracting the county and city names took far too long and having to fill in my own "0" values for localities with none of what I am seeking seems a waste of time.

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Which QGIS version are you using? I cannot confirm this behavior. Features without matching entry in the join layer are filled with NULL values but it does not affect the other features with matching entries in my experience. – underdark May 24 '13 at 22:32
Using 1.8 on a Mac. It didn't appear to behave that way using self generated shapefiles but this is a first-time use in QGIS of outside data-sets. – Lyle Browning May 25 '13 at 1:36
Are you sure the ID# have the same data type? Text and integer number may be considered as not equal. – AndreJ May 25 '13 at 6:46
I've tried both integer and text formats for the csv file but I don't know how to determine the data type for the shp file. Will do some experiments further with that. I also note that in trying to sort the ID#, the lead 1 goes all the way down as 1, 11, 111 and so forth rather than 1, 2, 3. – Lyle Browning May 26 '13 at 1:13
QGIS shows the column data types in the "Fields" tab. – underdark May 26 '13 at 7:47

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